CaO calcium oxide

Jon Schoonmaker, assistant professor of animal sciences at Purdue University, says adding a small amount of calcium oxide to distillers grains can improve the digestibility and nutrient value of some livestock feed mixes. Credit: Tom Campbell

Research by Purdue University scientist Jon Schoonmaker and his colleagues has shown that small amounts of calcium oxide can neutralize the acid in distillers grains, a commonly used alternative to corn in many livestock feed mixes.

"Incorporating calcium oxide into the feed mix represents a small increase in price for much better performance, " Schoonmaker said. "The benefits are especially important now that many producers are thinking about increasing the size of their herds to take advantage of improving market conditions."

Distillers grains are a relatively inexpensive and plentiful byproduct of ethanol production and retain many of the nutrients of the original corn used in the ethanol process.

The grains can be fed to animals in a wet form, with a 65 percent moisture content, or dried, at 10 percent.

The problem is that distillers grains retain the sulfuric acid used to control the starch fermentation during ethanol production. Since the grain is highly acidic, it is difficult for cattle to fully digest. The undigested feed is essentially empty calories, like junk food, because the animal gets no nutritional value from it.

Adding the calcium oxide, or CaO, directly to the ration mix at a rate of 1 percent of the total dry matter made the distillers grains less acidic, more digestible and therefore more nutritious, leading to better growth performance among test cattle, Schoonmaker said. Adding the CaO directly to the ration saves time and labor compared with the more traditional method of pre-treating low-quality roughages like corn stover while they are still in the field.